1. Field of Invention
The present invention relates to a manufacturing method of a phase change memory.
2. Description of Related Art
Electronic products (such as mobile phones, tablet computers and digital cameras) generally include memory devices for storing date. General memory device stores information through the storage nodes on the memory cells. Among them, a phase change memory stores data through the resistance state (for example: high resistance and low resistance) of the memory device. The phase change memory may include a material which is able to be transferred between different phases (for example: crystalline phase and amorphous phase). These different phases make the memory unit have resistance states with different resistance values, so as to represent different values for the storage of date.
During the operation of the phase change memory, currents are applied to increase temperature of the memory unit, and the phase of the material is changed. Generally, there exists larger contact area between a heater and a coupled memory unit in the phase change memory unit, and therefore that increases pores and defects at the contact surface. In addition, the currents need to be increased, since the heating and cooling rate is too slow (which means the transition rate between high resistance and low resistance is not fast enough). However, the traditional technique for manufacturing the heater having small contact area requires accurate alignment mechanism, which makes the process complicate and difficult to be controlled, and thus relatively increases the cost of the phase change memory. Therefore, it is necessary in the industry to develop a novel and efficiency process for manufacturing the phase change memory.